The present invention relates to a signal lamp of the type used with motor vehicles. More particularly, the invention relates to a signal lamp which when switched off presents a uniform external appearance of the lamp while being capable of presenting different signal colors in operation.
Such a signal lamp is disclosed in the German specification DE-OS No. 33 26 199. This specification discloses a signal lamp for motor vehicles including a pink cover glass and another colorful filter in its interior, whereby a red, yellow or even white signal light can be produced depending on the chosen color of the filter. In order to give the cover glass, despite its own pink color, a strong red color that is not, or at most minimally, influenced by the color of the internal filter while the light source of the signal lamp is switched off, red-colored stripes are provided in the lamp between the internal filter and the outside. Heretofore, the various arrangements of the stripes has presented certain disadvantages. For example, either only a small amount of light produced by the light source is available or the entire surface of the cover glass is not available for signalling. Furthermore, some arrangements of these strips are not particularly suited to reduce the influence of the internal filter on the color of the color glass while the signal lamp is switched off. The influence of the present red-colored stripes on the color of the signal light cannot be totally avoided despite great technical efforts.